If you need to cancel an Allegiant flight, the process is relatively straightforward. You can visit Allegiant website. From there, you can select the option to cancel your flight. Keep in mind that there may be a cancellation fee, and the remaining balance will typically be issued as a credit for future travel. If you need any assistance related to Cancel Allegiant Flight, you can visit the Airlines Pet Policy. Passenger can also call at 702-505-8888 or +1-844-902-4930 (OTA Skip-Waiting).